Metal honeycomb catalyst support have been proposed for converter for automobiles. One way to make a metal honeycomb is to lay a corrugated strip of metal on a flat strip of metal, and to wind the two strips upon themselves to make a spiral. Another way to make a honeycomb is to fold a strip of metal back and forth upon itself. U.S. Pat. No. 4,402,871 describes such a honeycomb. The face of the honeycomb can have any shape such as a circle or an ellipse, which is commonly used for automobile converters. These folded honeycombs are anchored in place in a metal shell or housing.
While many techniques have been used to assemble the honeycomb into the housing, many arrangements have been unable to survive severe automotive industry tests known as the Hot Shake Test, the Hot Cycling Test, combinations of these tests, cold vibration testing, water quench testing, and impact testing.
The Hot Shake test involves oscillating (50 to 200 Hertz and 28 to 80 G inertial loading) the device in a vertical, radial or angular attitude at a high temperature (between 800 and 1050 degrees C.; 1472 to 1922 degrees F., respectively) with exhaust gas from a gas burner or a running internal combustion Engine simultaneously passing through the device. If the device telescopes, or displays separation or folding over of the leading or upstream edges of the foil leaves, or shows other mechanical deformation or breakage up to a predetermined time, e.g., 5 to 200 hours, the device is said to fail the test.
The Hot Cycling Test is ran with exhaust flowing at 800 to 1050 degrees C.; (1472 to 1922 degrees F.) and cycled to 120 to 200 degrees C. once every 13 to 20 minutes for up to 300 hours. Telescoping or separation of the metal foil strips, or mechanical deformation, cracking or breakage is considered a failure.
Also, the Hot Shake Test and the Hot Cycling Test are sometimes combined, that is, the two tests are conducted simultaneously or superimposed one on the other.
The Hot Shake Test and the Hot Cycling Test are hereinafter called "Hot Tests." While they have proved very difficult to survive, the honeycomb structures of the present invention are designed to survive these Hot Tests and other tests similar in nature and effect that are known in the industry.
From the foregoing, it will be appreciated that metal honeycomb bodies having increase structural and mechanical durability and their method of manufacture are in need, particularly by the automotive industry.